I've seen devices before that will raise and lower a TV in a cabinet. Might something like that suit your needs? I think I've seen them before in the back pages of something like Popular mechanics, Wood Magazine, or one of the other ones.

Good luck

BV012704

02:02AM | 08/29/16

How about those lift tables for working on a motorcycle? Put it under your regular table, and jack it up. You might check a Harbor Freight store for some ideas. There are also pallet lifters that might be useable. A simple lever and rocker system might be constructed to lift each end, out of common construction materials. When up the lever might be on the floor, and the weight of the table would be over center, it would not come down. You might know some woodworking craftsmen that could work out the details.

BV012704

02:10AM | 08/29/16

How about those lift tables for working on a motorcycle? Put it under your regular table, and jack it up. You might check a Harbor Freight store for some ideas. There are also pallet lifters that might be useable. A simple lever and rocker system might be constructed to lift each end, out of common construction materials. When up the lever might be on the floor, and the weight of the table would be over center, it would not come down. You might know some woodworking craftsmen that could work out the details.

BV012705

08:16AM | 08/29/16

varidesk.com has models that raise and lower your computer. I saw prices at $200 and $400

BV012704

08:26PM | 08/29/16

How about those lift tables for working on a motorcycle? Put it under your regular table, and jack it up. You might check a Harbor Freight store for some ideas. There are also pallet lifters that might be useable. A simple lever and rocker system might be constructed to lift each end, out of common construction materials. When up the lever might be on the floor, and the weight of the table would be over center, it would not come down. You might know some woodworking craftsmen that could work out the details.